Encourage library staff to take public transportation (if its an option in your area). Many universities offer such perks as free bus passes for students and staff. One of the aspects I loved about working at the University of Colorado at Boulder was this benefit they called the Eco-Pass. I took the bus to work (even to the airport in Denver) for free, never had to worry about parking or paying to park. I read somewhere that Arizona State in Tempe offers this same benefit. I’m sure other places do as well. If not, think about carpooling. In the end, it saves the individual money, saves the institution from providing more parking facilities, offers a great perk for potential employees, all while cutting back on car emissions.
Additional comment: I just read that offering this transit benefit to employees is tax free under IRS codes!